1. Field of the Invention
This invention relates to a new diphenylamine compound that is a precursor for a phenazine dye. The diphenylamine compound comprises, in an ortho position to the amine of the diphenylamine, a sulfonyldiamido group that is capable of releasing a sulfonylamine fragment upon oxidation. It also relates to preparation of a phenazine dye and a sulfonylamine fragment from such a diphenylamine compound. It further relates to the use of such a new diphenylamine compound in photographic materials for producing silver images and dye images. It also relates to use of such new diphenylamine compounds with imaging materials that are responsive to ammonia or an amine released upon heating.
2. Description of the State of the Art
Photographic materials for producing silver images and dye images are known. The dye image in such materials is generally produced by a coupling reaction in which a developing agent is oxidized upon development of photographic silver halide in the material, followed by reaction of the resulting oxidized form of the developing agent with a coupling agent to produce a dye image. It has been desirable to provide alternative means for producing a dye image, especially a dye image that enhances a silver image, other than by a coupling reaction. The formation of dyes by means of new diphenylamine compounds according to the invention does not require a coupling reaction.
Production of reversal color images, also known as positive dye images, comprising developing a silver image in an imagewise exposed photographic material is also known. Such reversal color images and processes for producing such images are described in, for example, U.S. Pat. No. 4,035,184 and U.S. Pat. No. 3,938,995. These patents describe production of a dye image which includes reaction of a color-forming coupler with the oxidized form of an N,N-dialkyl-p-phenylenediamine. Neither of these patents relate to formation of a dye image by means of oxidation of a dye precursor and releasing of a group that is capable of thermally releasing ammonia or an amine. The present invention also avoids the need for a coupling reaction to produce a dye.
Reducing agents are known which upon oxidation intramolecularly react to form a heterocyclic ring, such as a phenazine ring. The reducing agents are described in, for example, U.S. Pat. No. 2,622,603 and U.S. Pat. No. 3,482,971. The compounds in these patents (a) lack a sulfonyldiamido group that is capable of releasing a sulfonylamine fragment and (b) lack capability of thermally releasing ammonia or an amine.
Imaging compounds that are responsive to or activated by ammonia or an amine are also known. Examples of such imaging compounds are described in, for example, published patent application WO 80/01322 published June 26, 1980. In such an imaging material phthalaldehyde is an imaging component that forms a dye in response to action by ammonia or an amine released from a cobalt(III) complex. None of these ammonia or amine responsive imaging materials contain a diphenylamine compound comprising a sulfonyldiamido group that is capable of aiding and augmenting imaging upon thermal processing.
The term "photographic material" herein means photographic elements and photographic compositions. For instance, photographic material herein includes photographic elements and photographic compositions comprising photographic silver halide and a dye precursor according to the invention.